View Full Version : High flow thermostat?

04-10-2017, 02:02 PM
I'm planning to head to Sacramento for the national Falcon convention this year, including the "Cruise Old Sacramento" event. I'm picturing slow speeds on a hot July day, and have been thinking about a high-flow thermostat, like a Robert Shaw or others to help with low speed cooling. Anybody have thoughts on that?

I'm currently running a stock water pump, Silla aluminum radiator, stock Ford-style fan shroud and a 180 degree 'stat, which puts my gauge at about 1/4 up here in (cooler) Oregon. Seems to work fine, although when I idle in traffic for a while, the idle seems to slow slightly and gets a little more ragged.

I'm looking to combat overheating at slow speeds wherever I drive.

04-10-2017, 09:48 PM
I'm not sure just a thermostat is the answer. Finding the correct combination of things to improve cooling is tough, sometimes. On my 289 I tried many things to help it cool and some of my changes were to use less antifreeze. Great for winter, but in summer it really only adds rust inhibitors. So maybe a 25% mix may help. I used a bit more, about 35% mix, and a better-than-stock fan, a good radiator, added an external cooling fan in front, and kept the thermostat. Seems to be doing OK now, but Seattle is not Sacramento.

Consider making a timing change, as this can alter temps too. Make sure your mechanical advance and vacuum advance are working. Slightly more advance at lower speeds, but not enough to cause detonation under load, can help minimize overheating too.

Good luck! It can be a challenge.

04-11-2017, 07:37 PM
A good six blade rigid fan (not a flex fan) and a shroud will do wonders.

six blade fan (http://www.speedwaymotors.com/Flex-a-lite-Heavy-Duty-Steel-Cooling-Fan,1846.html)

You can also create a lower air dam to help direct additional air flow through the radiator. There is a piece of steel that is part of the unibody behind the bumper and under the radiator. Attach a piece of black 1/4" HDPE as wide as will fit and cut it to hang below the bumper by several inches.

Replace your antifreeze for straight distilled water and add a bottle of Water Wetter (https://www.redlineoil.com/Products.aspx?pcid=10). This is a good Summer time solution. Don't run it like this in the Winter or it may freeze.

Check your thermostat on your stove to see when it opens. I use an 180-degree unit in my 62 with the 331. I typically drill a small hole at the edge and install it so the hole is at the top to help eliminate air pockets.

04-12-2017, 09:30 AM
I failed to mention that I'm using a 17" flex fan with my shroud. It sits about half in/half out of the shroud.

I've heard that a flex fan actually helps with low-speed cooling, then flattens out and reduces drag at highway speeds. I guess I'm confused as to which one would work better at low speeds.

04-12-2017, 07:21 PM
I had so many problems with my 347 overheating in my 64. It was one of the most frustrating things I dealt with. I tried different thermostats, none, plates with different sized holes to slow the water transfer, different fans, made a fan shroud, water wetter, some anti-freeze, none, on and on.
Finally I found an advertisement on ebay for a four core radiator that guaranteed it would cool my car. Installed that, along with the shroud and it never overheats now. My brother with a 64 Ford Fairlane high horsepower car bought a radiator from the same place and it isn't helping him much. So..........???
I empathize with you and hope some of these tips help you.
I am also planning on taking my 64 to Sacramento, meeting up with the group coming from back east in either Spokane or here in Everett.
Hope to meet you then. Larry

04-13-2017, 06:00 AM
Thanks for all the info guys. I'm not sure I want to change radiators just yet, but another thought- thermal fan clutch. Does anyone have experience with these? If so, can you recommend one for a 289?

04-13-2017, 06:31 PM
On my 289 I tried many things to help it cool and some of my changes were to use less antifreeze. Great for winter, but in summer it really only adds rust inhibitors. So maybe a 25% mix may help. I used a bit more, about 35% mix, ..

I live in Tampa and the coldest temperature I will ever see might be 28 degrees. I do not need coolant that will prevent freezing to -34 degrees. Increasing the percentage of water increases the heat transfer rate. Roger's recommendation of a 25/75 blend vs 50/50 is good advice. These are notes that I saved on this topic:
"No matter which type or color your antifreeze is, it will transfer heat away most efficiently when blended with the proper amount of water - a mixture percentage based on the lowest temperatures typically seen in your climate. Most regions are best suited to a 50/50 water-antifreeze mixture which will provide protection from a low of -34F to a high of 265F. In addition, maintaining proper freeze point protection ensures corrosion inhibitors remain at intended levels." "The manufacturer's recommendation: The standard recommendation is to use a 50/50 mix of antifreeze and water. This represents a compromise between cooling efficiency and the ability to prevent the mix from freezing during cold weather. After all, the initial purpose of antifreeze is to prevent freezing. But a 50/50 mix does not give the best cooling. For improved cooling in hot weather, we should use less antifreeze and more water, perhaps going to a 25/75. Everyone knows antifreeze prevents corrosion, and corrosion is bad. True, but even a 10/90 ratio of antifreeze to water will serve the purposes of inhibiting corrosion, at least according to one source of information." See: http://www.challengers101.com/CoolantMix.html
My Falcon's coolant capacity = 14.5 quarts (3.6 gallons). A 25/75 ratio fresh fill would be approximated by mixing one (0.9) gallon of straight coolant and topping it off with 2.7 gallons of water, or 1.8 gallons of 50/50 blend plus 1.8 gallons of water. That would give 13-psi boiling/freezing temperatures of 260/12.2 and a 10% higher specific heat compared to 265/-34 for a 50/50 mix. See: http://www.engineeringtoolbox.com/ethylene-glycol-d_146.html

I also want to add this. My 1963 Ford Falcon owner's manual says that the normal operating temperature is in between the two inner markings on the temperature gauge:


That means that the gauge can swing a good ways to the right of center and still not be overheating. Straight up and down is the normal operating temperature of 190 degrees. The engine can go hotter than that and still be OK. It is only overheating if the gauge pegs all the way to the right. Otherwise, don't worry about it.
Here are my related notes on oil temperatures: "For a dual-purpose car, engine oil needs to be at least 220 degrees F to burn off all the deposits and accumulated water vapor. Cold engine oil causes excessive frictional drag on the bearings and cylinder walls. A quality conventional motor oil will tolerate oil sump temperatures of up to 250 degrees, but starts breaking down over 275 degrees. The traditional approach is to try to hold oil temperatures between 230 and 260 degrees."

04-14-2017, 04:55 AM
I've heard about more water/less antifreeze from several sources now; I'm going to give that a try.

Looking forward to seeing you in Sacramento.

04-15-2017, 05:29 AM
I've heard about more water/less antifreeze from several sources now; I'm going to give that a try.

It is a quick and easy fix. Just drain out 1.75 gallons of 50/50 coolant (you can save it to re-use) and add 1.75 gallons of distilled water.

Whamo! You have 25/75 coolant with a 10% better heat transfer capacity.